Chirality and Gravitational Parity Violation

In this review, parity‐violating gravitational potentials are presented as possible sources of both true and false chirality. In particular, whereas phenomenological long‐range spin‐dependent gravitational potentials contain both truly and falsely chiral terms, it is shown that there are models that extend general relativity including also coupling of fermionic degrees of freedom to gravity in the presence of torsion, which give place to short‐range truly chiral interactions similar to that usually considered in molecular physics. Physical mechanisms which give place to gravitational parity violation together with the expected size of the effects and their experimental constraints are discussed. Finally, the possible role of parity‐violating gravity in the origin of homochirality and a road map for future research works in quantum chemistry is presented. Chirality 27:375–381, 2015.© 2015 Wiley Periodicals, Inc.     

Females of four mole species of genus Talpa (Insectivora,mammalia) are true hermaphrodites with ovotestes

We studied the anatomical, histological, and genetic features of the sexual tract in four European mole species of the genus Talpa (Insectivora, mammalia): T. occidentalis, T. europaea, T. romana, and T. stankovici. All XY individuals had a normal male phenotype, whereas all XX individuals in all four species had features that identified them as intersexes. These individuals were nonetheless presumed to be functionally fertile females. Intersexuality was manifested mainly as gonadal hermaphroditism, with all females possessing bilateral ovotestes. The gonads were composed of a small portion of histologically normal ovarian tissue and a variably sized, generally large mass of disgenetic testicular tissue, accompanied by a small, rudimentary epididymis. The rest of the sexual tract was typically female, including oviducts, uterus, and vagina of normal appearance. Polymerase chain reaction (PCR) and Southern blotting analyses showed that the mammalian testis-determining gene SRY is present in males but not in females. Part of the conserved sequence of the mole SRY gene was cloned and sequenced after PCR amplification in two of the four mole species (T. occidentalis from Spain and T. romana from Italy). Sequences were identical in these two species and were very similar to those of the human and mouse SRY gene. Our findings constitute the first evidence of the existence of a genus-specific case of true hermaphroditism, probably due to a very ancient mutation that fixed in populations of the ancestral species from which contemporary moles evolved. The possible nature of this mutation is discussed with regard to the cytologic, histologic, and genetic features of the gonads in Talpa females. © 1996 Wiley-Liss, Inc.     

Absence of odour-mediated avoidance of heterospecific competitors by the predatory mite Phytoseiulus persimilis

Arthropods use odours associated with the presence of their food, enemies and competitors when searching for patches. Responses to these odours therefore determine the spatial distribution of animals, and are decisive for the occurrence and strength of interactions among species. Therefore, a logical first step in studying food web interactions is the analysis of behaviour of individuals that are searching for patches of food. We followed this approach when studying interactions in an artificial food web occurring on greenhouse cucumber in the Netherlands. In an earlier paper we found that one of the predators of the food web, the predatory mite Phytoseiulus persimilis Athias-Henriot, used to control spider mites, discriminates between odours from plants with spider mites, Tetranychus urticae Koch, and plants with spider mites plus conspecific predators. The odours used for discrimination are produced by adult prey in response to the presence of predators, and probably serve as an alarm pheromone to warn related spider mites. Other predator species may also trigger production of this alarm pheromone, which P. persimilis could use in turn to avoid plants with heterospecific predators. We therefore studied the response of the latter to odours from plants with spider mites and 3 other predator species, i.e. the generalist predatory bug Orius laevigatus (Fieber), the polyphagous thrips Frankliniella occidentalis and the spider-mite predator Neoseiulus californicus (McGregor). Both olfactometer and greenhouse release experiments yielded no evidence that P. persimilis avoids plants with any of the 3 heterospecific predators. This suggests that these predators do not elicit production of alarm pheromones in spider mites, and we argue that this is caused by a lack of coevolutionary history. The consequences of the lack of avoidance of heterospecific predators for interactions in food webs and biological control are discussed.     

Effect of harvest date and nitrogen fertilization rate on the nutritive value of amaranth forage (Amaranthus hypochondriacus)

This study was conducted to assess effects of harvest date (i.e., 40 and 60 d after planting) and N fertilization rate (i.e., 120, 180, 240 kg N/ha) on the nutritive value of amaranth forage (Amaranthus hypochondriacus) using a factorial experiment with a randomized complete block design. The content of dry matter (DM), crude protein (CP), true protein (TP), ether extract (EE), water soluble carbohydrates (WSC), ash-free neutral detergent fiber (NDFom), ash-free acid detergent fiber (ADFom), lignin(sa), ash, Ca, P, Na, K, oxalic acid and nitrate were determined. Soluble CP (SP) and protein fractions non-protein N (A), true protein rapidly degraded in the rumen (B₁), true protein degraded in the rumen at a moderate rate (B₂), true protein associated with the cell wall and slowly degraded in the rumen (B₃) and acid detergent insoluble CP (C) were measured according to the Cornell Net Carbohydrate and Protein System. In vitro gas production (IVGP), OM disappearance (OMD) and NDFom disappearance (NDFD) were determined using a gas production technique. Results showed that the later harvest date increased (P<0.05) DM, EE, WSC, NDFom, ADFom, lignin(sa), B₃ and C; while CP, TP, ash, Ca, P, K, SP, A, B₁, B₂, nitrate, total and soluble oxalic acid, IVGP, b (i.e., gas production from the insoluble fermentable fractions at 120 h), c (i.e., rate of gas production during incubation), OMD and NDFD decreased (P<0.05). With increasing N fertilization rate, CP, TP, EE, P, nitrate, oxalic acid, SP, A, b, OMD and NDFD increased (P<0.05), however B₂ declined (P<0.05). Increasing N fertilization increased yield, CP concentration and nutrient digestibility. At 40 d after planting use of amaranth forage as a ruminant feed is limited due to its high nitrate content. However, at 60 d, although a depression in digestibility and CP content occurred, this forage has the potential as a ruminant feed due to the much lower nitrate levels.     

胰岛β细胞"质"、"量"的辩证关系——"质"的三要素

高血糖是糖尿病典型的病理特征,血糖的波动是决定糖尿病患者是否出现并发症的重要因素,而由胰岛β细胞合成分泌的胰岛素,是体内唯一可以降低血糖的多肽类激素.胰岛β细胞"质"与"量"决定着体内胰岛素分泌情况和血糖的调控.围绕"促进β细胞损伤修复,提升胰岛β细胞质量是治疗糖尿病的核心"之理念,提出构成胰岛β细胞"质"的三要素:细胞结构、"真""假"胰岛素和胰岛素调节型分泌.旨在为β细胞质量评价和糖尿病机制研究提供一定的理论参考.     

灰绒泡菌生活史及其子实体发育过程的显微观察

为明确灰绒泡菌Physarum cinereum的个体发育特征,本研究在实验室条件下完成了该菌的生活史,并对其子实体发育过程进行显微观察。灰绒泡菌P. cinereum孢子萌发方式为裂式,显型原质团水白色;子实体形态建成可分为孢囊形成期和孢囊成熟期,孢囊成熟期幼孢囊颜色随着孢子的形成呈现白色-红棕色-黑褐色逐渐加深的变化;子实体在发育过程中孢丝形成后原生质割裂形成孢子。     

三种棉盲蝽对不同棉花品种的选择偏好性及种群动态

【目的】明确我国华北地区棉盲蝽优势种对不同种棉花品种的选择偏好性,以及这几种盲蝽的种群动态及发生规律。【方法】2013和2014年通过小区随机排列田间系统调查的方法,比较分析了中黑盲蝽Adelphocoris suturalis(Jakovlev)、三点盲蝽Adelphocoris fasciaticollis(Reuter)和绿盲蝽Apolygus lucorum(Meyer-Dür)对12个棉花品种的选择偏好性,种群动态及与温度的关系。【结果】3种盲蝽均对石亚系1号表现出明显偏好性,对N73Deltapine FO表现出明显的不偏好性。棉盲蝽在每年7月初开始危害,7月下旬及8月上旬盲蝽种群密度达到峰值,9月上旬种群密度逐渐降低,9月中下旬盲蝽迁出棉田。在本实验调查的温度范围内(17~35℃),盲蝽种群密度随着温度升高而增大。【结论】棉盲蝽对不同品种有明显选择偏好性,盲蝽种群大的地区推荐种植盲蝽厌食品种。     

Multiple testing with discrete data: Proportion of true null hypotheses and two adaptive FDR procedures

We consider multiple testing with false discovery rate (FDR) control when p values have discrete and heterogeneous null distributions. We propose a new estimator of the proportion of true null hypotheses and demonstrate that it is less upwardly biased than Storey's estimator and two other estimators. The new estimator induces two adaptive procedures, that is, an adaptive Benjamini–Hochberg (BH) procedure and an adaptive Benjamini–Hochberg–Heyse (BHH) procedure. We prove that the adaptive BH (aBH) procedure is conservative nonasymptotically. Through simulation studies, we show that these procedures are usually more powerful than their nonadaptive counterparts and that the adaptive BHH procedure is usually more powerful than the aBH procedure and a procedure based on randomized p‐value. The adaptive procedures are applied to a study of HIV vaccine efficacy, where they identify more differentially polymorphic positions than the BH procedure at the same FDR level.     

Secretion-grooming in the water bug Plea minutissima: a chemical defence against microorganisms interfering with the hydrofuge properties of the respiratory region

Abstract. 1. The water bug Plea minutissima Leach (Hemiptera: Pleidae) from time to time crawls out of the water and distributes secretion from its metathoracic glands over the ventral part of its body. By this 'secretion-grooming' antiseptic gland substances, mostly hydrogen peroxide, are applied to the hydrofuge hairs which hold the respiratory air bubble.
2. When the bugs are prevented from leaving the water, their mortality increases significantly, and individuals lacking the air bubble are observed. Examination of such bugs with Scanning Electron Microscopy techniques reveals bacteria growing on their hydrofuge hairs, whereas in bugs allowed to secretion-groom the hairs are not contaminated by microorganisms.
3. Artificial application of diluted metathoracic gland secretion on the body surface of P. minutissima kills bacteria, while specific ciliates, which never colonize the respiratory region, are not harmed by the secretion.
4. It can be concluded that secretion-grooming prevents the contamination of the hydrofuge respiratory region that leads to the wetting of the hydrofuge respiratory regions, resulting in the loss of the air bubble, and, finally, the drowning of the animals.
5. Other possible functions of the secretion, such as chemical defence against predators or wetting of the body surface, could not be demonstrated or seem unlikely.